It looks like towering flames, the filaments of
NGC 6979. It's a supernova remnant, sometimes identified as
Pickering's Triangle.
Edward Pickering was the director of the observatory where it was discovered. However it's also known as
Fleming's Triangular Wisp after
Williamina Fleming who actually discovered it.
The supernova remnant is part of the Veil Nebula in Cygnus (the Swan). The light from the supernova probably reached Earth over 5000 years ago. Since then the
interstellar shock waves [have plowed] through space sweeping up and exciting interstellar material. The glowing filaments are really more like long ripples in a sheet seen almost edge on, remarkably well separated into the glow of ionized hydrogen atoms shown in red and oxygen in blue hues.
Image Credit & Copyright: Sara Wager
Commentary credit: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)